Science: Work, Power and Efficiency Practice Problems:

Work = Force x Distance
Power = Work / Time
Percent Efficiency = Work
Output/Work Input x 100

Step 1: Write the equation
Step 2: Substitute with units
Step 3: Solve with units
rounding to the nearest tenth

1) It took 639 Newtons to push a table 21 meters. How much work was done?

Answer:

Ferromagnetism, physical phenomenon in which certain electrically uncharged materials strongly attract others. Two materials found in nature, lodestone (or magnetite, an oxide of iron, Fe3O4) and iron, have the ability to acquire such attractive powers, and they are often called natural ferromagnets.

Hope this help :)

Answer:

Explanation:

Since the forces are only in the x-direction, you could just add the two forces. The West is to the left, so it would be -25N with the negative sign indicating direction. The East is to the right, so that would be +50N.

50 + (-25) = 25N to the right or the positive i-hat direction

Answer:

The respiratory system is lined with a mucous membrane that secretes mucus. The mucus traps smaller particles like pollen or smoke. Hairlike structures called cilia line the mucous membrane and move the particles trapped in the mucus out of the nose.

Explanation:

Answer:

Explanation:

100 mph = 100 x 1760 x 3 / ( 60 x 60 )

= 146.67 ft / s

70 mph = 70 x 1760 x 3 / ( 60 x 60 )

= 102.67 ft/s

Let mass of the ball = m .

The ball which was moving with a velocity of 146.67 ft/s is turned back by the action of force of bat on the ball and it moved in opposite direction with velocity of - 102.67 ft/s ( - ve sign due to reversed direction )

If m be the mass of ball

change in momentum = m x 146.67 - ( - m x 102.67 )

=  m x 146.67 +  m x 102.67

= 249.34 m

Change in momentum = impulse = force x time

Putting the given values

249.34 m = force x 1 x 10⁻³ ( time = 10⁻³ s )

force = 249.34 m x 10³ poundal .

Here m is mass of the ball in lb .

Answer:750

Explanation:

50 times 15

Answer:

750 j

Explanation:

I took the test in k12

Answer:

When a bee stings, it injects methanoic acid into the skin which causes immense pain and irritation. Rubbing of baking soda on the sting area gives relief because, being alkaline in nature, baking soda neutralizes the effect of methanoic acid and gives relief.

Answer:

which class you are studying hear the everything is based on the tangent line I didn't even handle this I am sorry

A passive continental margin has a continental rise, while an active margin does not. Therefore, option A is correct.

Where there is no plate border to mark the transition from land to sea, this is known as a passive continental margin.

A good example is the east coast of the United States, where the plate boundary is a distance from the shore along the mid-Atlantic ridge. Little geological activity occurs along passive borders.

Volcanoes, mountain belts, and earthquakes all identify active margins. They lack a continental uplift and an abyssal plain, in contrast to passive margins.

The Pacific and North American Plate boundaries are visible along the west coast of the United States, which is an example of an active margin. Where there is no plate border to mark the transition from land to sea, this is known as a passive continental margin.

Thus, option A is correct.

To learn more about the passive continental margin, follow the link:

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Answer:

Ver respuesta en el procedimiento

Explanation:

En este caso, necesitamos la expresión que nos permite hallar el Trabajo realizado por un objeto a través de una distancia dada. Esa expresión es:

W = F * x   (1)

Donde:

W: Trabajo en Joules (J)

F: Fuerza en Newton (N)

x: Distancia o radio en metros (m)

En este caso, solo tenemos una masa de 800 lb, y la distancia que se esta recorriendo. No tenemos ningún dato adicional que nos diga si por ejemplo, es empujado por una persona o parecido, solo los datos de la masa que lleva la carreta. Por lo tanto, la única fuerza que podemos asumir se está ejerciendo, sería la fuerza del peso del objeto que se calcula así:

P = mg   (2)

Donde:

g: aceleración de gravedad (9,8 m/s²)

Ahora bien si reemplazamos (2) en (1) nos queda:

W = mgx  (3)

Y antes de realizar el cálculo debemos convertir la unidad de masa en libra a kilogramo, usando la siguiente conversión:  1 lb -----> 0,454 kg por tanto:

m = 800 * 0,454 = 363.2 kg

Ahora podemos usar (3) y calcular el trabajo:

W = 363,2 * 9,8 * 100

W = 355936 J o simplemente 355,936 kJ

Espero te sirva.

PD: También puedes usar el valor de gravedad como 10 m/s² y tendrás un resultado de 363200 J o 363,2 kJ.

Answer: Heating from the crust and mantle.

Explanation: Tremendous heat and pressure within the earth cause the hot magma to flow in convection currents. These currents cause the movement of the tectonic plates that make up the earth's crust.

The convection currents that cause this cycle to take place is driven by heating from the crust and mantle. Hence, option (a) is correct option.

A crucial idea that illustrates the changes between the three primary rock types is the "rock cycle" (metamorphic, igneous and sedimentary). Simply put, it is a series of processes that create and modify the various types of rocks found in the Earth's crust.

The solid crust of Earth serves as a heat insulator for the planet's warm interior. The molten rock in the mantle, below the crust, is known as magma. Convection currents are created by the intense heat and pressure that exists within the earth. The tectonic plates that make up the earth's crust shift as a result of these currents.

Learn more about rock cycle here:

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Answer:

A. The magnets used to lift metal or cars in a salvage/junk yard

Explanation:

An electromagnet  is defined as a type of magnet which are made up of wires in coil shape. Magnetic field in these wires are produced by electric current.

An example of an electromagnet is magnets used to lift metal or cars in a salvage/junk yard because a crane is used in junkyard to lift metal in which crane is attached to a iron disc and when electricity is off, the disc move downwards and placed near required metal and switch on the electricity when disc reaches on metal or cars to be lifted. This electricity generates magnetism in the iron disc and attract metal or cars from the junkyard.

Hence, the correct answer is "A. The magnets used to lift metal or cars in a salvage/junk yard".

Answer:

660

Explanation:

0.011kW = 11W

energy = 11 x 60

            = 660J

Answer:

please use the formula to find the current/use ohms law

Explanation:

I=v/r

Answer:

It conserves both energy and momentum in the collision at the same time. By design, when the balls collide the strings that hold them up are vertical (assuming balls are only swung from one side).

Explanation:

Hope This Helps!!

Answer:

liver (but avoid this during pregnancy)

red meat.

beans, such as red kidney beans, edamame beans and chickpeas.

nuts.

dried fruit – such as dried apricots.

fortified breakfast cereals.

soy bean flour.

Explanation:

Answer:

they share electrons between them.

Explanation:

taking the test rn lol i think its right

Answer:

a)  [tex]v_{oy}[/tex] = 0,  b)  t = 9.035 s, c) x = 587.275 m, d)  v_y = -88.54 m / s,

e) v = 109.84 m / s,  f)  θ = -53.7º

Explanation:

This exercise is a projectile launch

a) as the projectile is launched horizontally, its initial vertical velocity is zero

          [tex]v_{oy}[/tex] = 0

b) let's use the relation

          y = y₀ + v_{oy} t - ½ g t²

when reaching the ground y = 0 and the initial vertical velocity is v_{oy}=0

         0 = y₀ + 0 - ½ g t²

         t = [tex]\sqrt{ \frac{2 v_o}{g} }[/tex]

         t = [tex]\sqrt{ \frac{ 2 \ 400 }{ 9.8} }[/tex]

         t = 9.035 s

c) the horizontal distance is

         x = v₀ₓ t

         x = 65  9.035

         x = 587.275 m

d) the vertical speed when touching the ground

         v_y = [tex]v_{oy}[/tex] -gt

         v_y = 0 - 9.8 9.035

          v_y = -88.54 m / s

the negative sign indicates that the velocity is directed downwards

e) the velocity at this point

          v = [tex]\sqrt{ v_x^2 + v_y^2}[/tex]

          v = [tex]\sqrt{65^2 + 88.54^2}[/tex]

          v = 109.84 m / s

f) the direction of the velocity

let's use trigonometry

          tan θ = v_y / vₓ

          θ = tan⁻¹1 v_y / vₓ

          θ = tan⁻¹ (-88.54 / 65)

          θ = -53.7º

this angle is measured clockwise

Answer:

ology

Explanation:

Answer:

300km

Explanation:

To find the total distance traveled within the given time frame, we need to known that distance is the product speed and time;

  Distance  = Speed x time

For the first lap:

   Distance  = 100km/hr x 3hr = 300km

For the second lap;

     Distance  = 150km/hr x 2  = 300km

Distance  = 300km + 300km

So;

Distance = 300km

Answer:

the time of motion of the ball is 6.89 ms.

Explanation:

Given;

angular speed, ω = 38 rad/s

angular distance, θ = 15 degrees

Angular distance in radian;

[tex]\theta = 15^0 \times\frac{2\pi \ rad}{360^0} = 0.2618 \ rad[/tex]

Time of motion is calculated as;

[tex]time = \frac{angular \ distance}{angular \ speed} \\\\t= \frac{\theta}{\omega} = \frac{0.2618 \ rad}{38 \ rad/s} \\\\t = 6.89 \ \times 10^{-3} \ s\\\\t = 6.89 \ ms[/tex]

Therefore, the time of motion of the ball is 6.89 ms.

Answer:

Answer: D. Only R

Explanation:

The Principle Of Conservation Of Mechanical Energy

In the absence of friction, the total mechanical energy is conserved. That means that

Em=U+K is constant, being U the potential energy and K the kinetic energy.

At the top of the path (point Q), Joshua is at rest but his height is at a maximum. Thus his kinetic energy is zero.

At point P, Joshua is at the minimum level (potential energy zero) and his speed is at a maximum.

At point R, Joshua has some height and some speed which means he has both types of energy.

Answer: D. Only R

Answer:

I dont really know but i think its water type of energy

Explanation:

Hope it helps

Explanation:

Wavelength = speed of light/frequency

Answer is

[tex]6 \times {10}^{ - 7} [/tex]

Answer:

A

Explanation:

I only think its A because of the gravity part...sorry im not good at explaining

Answer:

Centi is the metric prefix for 0.01

KE = 8887.5 J

Given

speed = 15 m/s

weight = 79 kg

Required

KE-Kinetic energy

Solution

Energy is the ability to do work  

Energy because its motion is expressed as Kinetic energy (KE) which can be formulated as:  

[tex]\large {\boxed {\bold {KE = \frac {1} {2} mv ^ 2}}}[/tex]

Input the value :

KE = 1/2 x 79 kg x 15² m/s²

KE = 8887.5 J

Answer:

KE = 8887.5 J